Lismore is based on the tiny Island of Lismore, found between Mull and the Scottish mainland.
Lismore is not actually a distillery, rather they independently bottle Speyside whiskies from a secret Speyside distillery. Lismore is bottled by J&G Grant, the owner of the Glenfarclas distillery.
The Lismore brand was first created in 1974 by the Lundie family. The Lundie family were successful whisky brokers, and so had access to some wonderful cask stocks. Eventually, the second generation of Lundie's (Alan & Bruce) realised that they could siphon off some of the very best casks and bottle them under their own brand.
The provenance of their whisky is a closely guarded secret, but we're assured that this "recipe" hasn't changed since the brand was founded.